Selenium Biofortification Enhanced miR167a Expression in Broccoli Extracellular Vesicles Inducing Apoptosis in Human Pancreatic Cancer Cells by Targeting IRS1

Purpose: Pancreatic adenocarcinoma (PAAD) presents an extremely high morbidity and mortality rate. Broccoli has excellent anti-cancer properties. However, the dosage and serious side effects still limit the application of broccoli and its derivatives for cancer therapy. Recently, extracellular vesicles (EVs) derived from plants are emerging as novel therapeutic agents. Thus, we conducted this study to determine the effectiveness of EVs isolated from Se-riched broccoli (Se-BDEVs) and conventional broccoli (cBDEVs) for the treatment of PAAD.

Methods: In this study, we first isolated Se-BDEVs and cBDEVs by a differential centrifugation method, and characterized them by using nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM). Then, miRNA-seq was combined with target genes prediction, and functional enrichment analysis to reveal the potential function of Se-BDEVs and cBDEVs. Finally, the functional verification was conducted in PANC-1 cells.

Results: Se-BDEVs and cBDEVs exhibited similar characteristics in size and morphology. Subsequent miRNA-seq revealed the expression of miRNAs in Se-BDEVs and cBDEVs. Using a combination of miRNA target prediction and KEGG functional analysis, we found miRNAs in Se-BDEVs and cBDEVs may play an important role in treating pancreatic cancer. Indeed, our in vitro study showed that Se-BDEVs had greater anti-PAAD potency than cBDEVs due to increased bna-miR167a_R-2 (miR167a) expression. Transfection with miR167a mimics significantly induced apoptosis of PANC-1 cells. Mechanistically, further bioinformatics analysis showed that IRS1, which is involved in the PI3K-AKT pathway, is the key target gene of miR167a.

Conclusion: This study highlights the role of miR167a transported by Se-BDEVs which could be a new tool for counteracting tumorigenesis.